Abstract
ZIP transporters are essential for uptake micronutrient ions (Zn, Fe, Mn and Cu), while they also erroneously transport toxic metal ions and cause the accumulation in plant. However, little is known about the structure concerning ion specificity of ZIP. At the last JSPP meeting, we reported that TjZNT2, the ZIP transporter of Thlaspi japonicum (Brassicaceae), deleted N-terminal region (36 a.a.) acquired the ability of Zn transport and suggested the involvement of N-terminal structure in metal ion specificity. We constructed three kinds of TjZNT2 mutants with different N-terminal length and quantified their Zn65 transport activity, suggested that the inhibitory effect of Zn transport tend to be proportional to the size of N-terminal. We also found that truncated TjZNT2 lost Mn transport activity and the N-terminal acts not only Zn but also other substrate metal ion. Now, we examine further the function of TjZNT2 in planta.
